that 'high rev' box from ehrenberg, looks EXACTLY like the chinese box they sell at oreilly's.
get a MOPAR not new box, or you will be right back where you were. He sells 'fix-it' parts that are part, of a small parts kit for more than the kit. He's in it for the money unless you talk to him, and has vouched for an engine build that left one member robbed in value.
These are the exact problems i had building a previous 74 road runner where the new chinese parts failed after a few drives -only a few drives over 100 mph.
The ignition box failed multiple times and the voltage regulator once allowed over 16 volts which left me stranded with blown coils several times. The car drove for a while with the bad voltage regulator.
At any rate keep a spare box, coil, and starter in the trunk of your ride
